1. Technical Field
The present invention relates to a head mounted display device.
2. Related Art
A head mounted display device (HMD) that is a display device mounted on a head is known. The head mounted display device, for example, generates an image light using a liquid crystal display and a light source, guides the generated image light to the eyes of a user using a projection optical system and a light guide plate, and causes the user to visually recognize a virtual image. Of the head mounted display device, there are two types: a transmission type device with which the user can visually recognize an outside scene in addition to the virtual image and a non-transmission type device with which the user cannot visually recognize the outside scene. There are two types of the transmission type head mounted display device: an optical transmission type head mounted display device and a video transmission type head mounted display device.
In JP-A-2006-195084, a technology is disclosed, in which a state of retina of the eyes of the user seeing the image displayed in the display device is detected, a region where the user is seeing in the display image is specified based on the detected state of the retina, and then, regions except the region where the user is seeing are blurred. In JP-A-2011-205195, a technology is disclosed, in which, in an image processing device that enables the user to stereoscopically and visually recognize a two-dimensional image by making the display image for the left eye and the display image for the right eye different from each other, a parallactic angle becomes equal to or greater than a certain level, which is a difference between a convergence angle of the user when the stereoscopic image is visually recognized and a convergence angle of the user when a display screen of a two-dimensional image which is different from the stereoscopic image is visually recognized. In addition, in JP-A-2012-13940, a technology is disclosed, in which, in a display device capable of displaying the display image for the left eye and the display image for the right eye, a character image such as a sub-title is displayed such that the convergence angle is formed, which matches the convergence angle of the display image visually recognized by the user.
As disclosed in JP-A-2011-205195, when significantly changing the convergence angle of the user, there has been a problem in that a tired feeling is given to the user. However, in the technology disclosed in JP-A-2006-195084, JP-A-2011-205195, and JP-A-2012-13940, a display mode of a display device according to a change of a direction of line of sights of the user who visually recognizes the display image is not considered. Therefore, there has been room for improvement for a method of causing the user to stereoscopically and visually recognize the display image. In addition, in the technical field of the display device in the related art, it has been desired to minimize size, to make it easy to manufacture, and to improve usability.